FUEL 182 |
| Biological methanogenesis from monomethylamine, dimethylamine, or trimethylamine is initiated by one of three methyltransferases that methylate a cognate corrinoid protein with a specific methylamine. Each methylamine methyltransferase contains an unusual electrophilic residue, pyrrolysine. Pyrrolysine is inserted during translation under the direction of an amber (TAG=UAG) codon found in each methyltransferase gene. UAG translation as pyrrolysine requires a pyrrolysine-specific tRNA and pyrrolysyl-tRNA synthetase. Pyrrolysine biosynthesis and the genetic encoding of pyrrolysine in total requires only five gene products, and these are readily transmissible to a naïve organism. Methylamine methyltransferase lacking pyrrolysine, due to either site-directed mutagenesis, or pyrrolysine modification, have greatly diminished activity in methylating corrinoid cofactors. These results suggest that methane formation from methylamines requires pyrrolysine as an essential catalytic residue; a result that is consistent with proposed models of pyrrolysine-containing methyltransferase catalysis during Co(I)corrinoid methylation with methylamines. |
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Hybrid Nanotechnologies for an Enhanced CO2 Fixation
8:50 AM-11:45 AM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 240/241, Oral
Division of Fuel Chemistry |